Development and implementation of standardized respiratory chain spectrophotometric assays for clinical diagnosis.

Diversity of respiratory chain spectrophotometric assays may lead to difficult comparison of results between centers. The French network of mitochondrial diseases diagnostic centers undertook comparison of the results obtained with different protocols in the French diagnostic centers. The diversity of protocols was shown to have striking consequences, which prompted the network to undertake standardization and optimization of the protocols with respect to clinical diagnosis, i.

Influence of mitochondrial DNA level on cellular energy metabolism: implications for mitochondrial diseases.

The total amount of cellular mitochondrial DNA (mtDNA) varies widely and seems to be related to the nature and metabolic state of tissues and cells in culture. It is not known, however, whether this variation has any significance in vivo, and to which extent it regulates energy production. To better understand the importance of the cellular mtDNA level, we studied the influence of a gradual reduction of mtDNA copy number on oxidative phosphorylation in two models: (a) a control human cell line treated with different concentrations of 2', 3'-dideoxycytidine, a nucleoside analogue that inhibits mtDNA replication by interfering with mitochondrial DNA polymerase gamma, and (b) a cell line derived from a patient presenting mtDNA depletion.

Effects of intermittent femoral nerve injections of bupivacaine, levobupivacaine, and ropivacaine on mitochondrial energy metabolism and intracellular calcium homeostasis in rat psoas muscle.

Background: Long-acting local anesthetics cause muscle damage. Moreover, long-acting local anesthetics act as uncoupler of oxidative phosphorylation in isolated mitochondria and enhance sarcoplasmic reticulum Ca(2+) release. The aim of the study was to evaluate effects of perineural injections of local anesthetics on mitochondrial energetic metabolism and intracellular calcium homeostasis in vivo.

Gradual alteration of mitochondrial structure and function by beta-amyloids: importance of membrane viscosity changes, energy deprivation, reactive oxygen species production, and cytochrome c release.

Intracellular amyloid beta-peptide (A beta) accumulation is considered to be a key pathogenic factor in sporadic Alzheimer's disease (AD), but the mechanisms by which it triggers neuronal dysfunction remain unclear. We hypothesized that gradual mitochondrial dysfunction could play a central role in both initiation and progression of sporadic AD. Thus, we analyzed changes in mitochondrial structure and function following direct exposure to increasing concentrations of A beta(1--42) and A beta(25--35) in order to look more closely at the relationships between mitochondrial membrane viscosity, ATP synthesis, ROS production, and cytochrome c release.

Time course of differential mitochondrial energy metabolism adaptation to chronic hypoxia in right and left ventricles.

Objective: The present study was designed to characterize mitochondrial adaptation to chronic hypoxia (CH) in the rat heart. Mitochondrial energy metabolism was differentially examined in both left and right ventricles since CH selectively triggers pulmonary hypertension and right ventricular hypertrophy.

Methods: Rats were exposed to a hypobaric environment for 2 or 3 weeks and compared with rats maintained in a normoxic environment.